Synthetic Studies of the 18-Membered Antitumor Macrolide, Tedanolide. 3. Stereocontrolled Synthesis of the C1-C12 Part via a Synthesis of the C1-C7 Fragment by a Mismatched but Efficient Sharpless Dihydroxylation and Its Coupling with the C8-C11 Fragment

Abstract

The C1-C12 part (4) of tedanolide (1) was synthesized starting from methyl (R)-3-hydroxy-2-methylpropionate (11a) via a coupling between the C1-C7 aldehyde (6) and the C8-C11 iodoalkene (7a). For a synthesis of 6, a mismatched but highly efficient Sharpless dihydroxylation of the α, β-unsaturated ester (15) with AD-mix-α was successfully applied. Compound 7a was synthesized using hydrozirconation to the alkyne (32).